The PI proposes to continue his studies on the molecular pathogenesis of AIDS-associated lymphomas. The PI has recently discovered that approximately 40% of the diffuse large cell lymphomas (DLCL) associated with AIDS contain rearrangements in the 5'noncoding region of the BCL-6 gene. In this project, he will further characterize the structural alterations of BCL-6 in DLCL, elucidate the biological consequences of BCL-6 alterations on tumor pathogenesis and Epstein-Barr virus gene expression, and attempt to identify additional genetic alterations associated with lymphomas in AIDS.